If you have an iPhone 5, then you need to make sure you are running iOS 10.3.4.
Apple has warned iPhone 5 users to download iOS 10.3.4 by November 3, as they may lose many features. It's a problem with GPS and the exact time and date for more phone options.
Apple uses GPS for date and time, and to show it is really necessary to update.
"If you do not update, you will stop features related to the correct date and time, such as the App Store, iCloud, email and web browsing," Apple said.
This also applies to iPad Wi-Fi + Cellular users, the iPhone 4S and older iPad models.
To upgrade the software, select Settings - General - Software Update.
If you do not upgrade by November 3rd, then you will need to manually plug your phone into a computer to upgrade the software.